Upstream code and resources for Chrome on iOS extensions.

ios/chrome/today_extension/today_metrics_logger.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IOS_CHROME_TODAY_EXTENSION_TODAY_METRICS_LOGGER_H_
+#define IOS_CHROME_TODAY_EXTENSION_TODAY_METRICS_LOGGER_H_
+
+#include <memory>
+#import "base/memory/ref_counted.h"
+#include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram_flattener.h"
+#include "base/metrics/histogram_snapshot_manager.h"
+#include "base/metrics/user_metrics_action.h"
+
+namespace base {
+
+class SequencedWorkerPool;
+class SequencedTaskRunner;
+
+}  // namespace base
+
+namespace {
+
+class TodayMetricsLog;
+class TodayMetricsServiceClient;
+
+}  // namespace
+
+class ValueMapPrefStore;
+class PrefRegistrySimple;
+class PrefService;
+
+// Utility class to create metrics log that can be pushed to Chrome. The
+// extension creates and fills the logs with UserAction. The upload is done by
+// the Chrome application.
+class TodayMetricsLogger : base::HistogramFlattener {
+ public:
+  // Singleton.
+  static TodayMetricsLogger* GetInstance();
+
+  // Records a user action. The log is saved in the user defaults after each
+  // action.
+  void RecordUserAction(base::UserMetricsAction action);
+
+  // Write the current log in the UserDefaults.
+  void PersistLogs();
+
+  // HistogramFlattener:
+  void RecordDelta(const base::HistogramBase& histogram,
+                   const base::HistogramSamples& snapshot) override;
+  void InconsistencyDetected(
+      base::HistogramBase::Inconsistency problem) override;
+  void UniqueInconsistencyDetected(
+      base::HistogramBase::Inconsistency problem) override;
+  void InconsistencyDetectedInLoggedCount(int amount) override;
+
+ private:
+  TodayMetricsLogger();
+  ~TodayMetricsLogger() override;
+
+  bool CreateNewLog();
+
+  base::MessageLoop message_loop_;
+  scoped_refptr<PrefRegistrySimple> pref_registry_;
+  std::unique_ptr<PrefService> pref_service_;
+  scoped_refptr<ValueMapPrefStore> value_map_prefs_;
+  scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner_;
+  std::unique_ptr<TodayMetricsLog> log_;
+  scoped_refptr<base::SequencedWorkerPool> thread_pool_;
+  std::unique_ptr<TodayMetricsServiceClient> metrics_service_client_;
+  base::HistogramSnapshotManager histogram_snapshot_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(TodayMetricsLogger);
+};
+
+#endif  // IOS_CHROME_TODAY_EXTENSION_TODAY_METRICS_LOGGER_H_